The invention is in the field of reproduction technology and is directed to a light beam deflection device for an originals scanner device or for a recording device. Such a scanner device usually comprises a light source that generates at least one light beam, a light beam deflection device, and an optical unit.
Given an originals scanner device, also referred to as an input scanner, a light beam generated in a scanner unit is conducted point-by-point and line-by-line across an original to be scanned, and the scan light reflected from the original or that has passed through the original is converted into an image signal in an optoelectronic transducer. Given a recording device, also referred to as a recorder, an exposer, or an output scanner, the light beam acquired in a scanner unit is intensity-modulated by an image signal for the recording of information and is conducted point-by-point and line-by-line across a light-sensitive recording material.
In the case of a flat bed apparatus, the holder for the original or the recording material is a planar surface across which the light beam is conducted point-by-point and line-by-line, and that moves relative to the scanner unit. In the case of an inside-drum device, the holder for the original or for the recording material is designed as a stationary half-shell or trough. The scanner unit moves parallel to the longitudinal axis of the holder and the light beam is conducted radially across the original or recording material perpendicular to the longitudinal axis.
An inside-drum recording device is disclosed, for example, by EP-A-0 354 028. The light beam deflection device therein is designed as a mirrored surface arranged transversely relative to the light propagation direction and is connected to a rotating shaft. The light beam is steered onto a recording material with the assistance of the mirrored surface.
During operation of the recording device, contaminants can collect at the mirrored surface and air turbulence can arise at high speeds due to the asymmetrical design relative to the rotational axis. Such air turbulence leads to noise, causes additional contamination in the region of the reflection face, and deteriorates the uniform rotation of the mirrored surface.
DE-A-41 24 229 already discloses a light beam deflection device having a light entry face and a light exit face for the perpendicularly deflected light beam, this light beam deflection device being comprised of a rotatably seated carrier prism and of a light-permeable deflection prism extending in the direction of a rotational axis. The surface of the deflection prism adjoining the carrier prism is designed as a reflection face that proceeds transversely relative to the rotational axis. The deflection prism is glued to the carrier prism and the two prisms supplement one another in at least certain regions to form a unit that is symmetrical relative to the rotational axis. Disk-shaped cover elements that project beyond the unit in the radial expanse thereof are arranged to the side of the unit.
Given this light beam deflection device, only slight air turbulence, contamination and rough running result due to the cover elements; manufacture, however, is comparatively involved since the cover elements must be exactly manufactured and must be precisely centered at the unit.
DE-A-43 04 499 discloses another light beam deflection device comprising a carrier prism and a deflection prism that are connected by gluing to form a rotatable unit. In this embodiment, the edges and corners of the unit that are not optically used are rounded, so that the unit comprises a spherical outside contour, at least in sections, as a result whereof only slight air turbulence likewise arises.
DE-A-41 30 977 discloses another light beam deflection device that is composed of a transparent body designed as a spherical segment that comprises a light entry face, a reflection face and a light exit face, and is further composed of a carrier member likewise fashioned as a spherical segment that is glued to the reflection layer with the transparent body. The unit formed of the transparent member and the carrier body is rotatable around an axis residing perpendicularly relative to the light entry face, and comprises an outside contour that is rotationally symmetrical at least with reference to the axis. Due to the spherical design of the light beam deflection device, it can rotate with a relatively high speed without creating significant air turbulence and running noise. What is disadvantageous, however, is that the light exit face is curved and that optical errors caused as a result thereof must be corrected in the beam path in an involved way.
Beyond this, the known light beam deflection devices exhibit the disadvantage that the glued connection of deflection prism and carrier prism, or of transparent member and carrier body, only allows a relatively slight mechanical loading, so that the permitted speed of the light beam deflection devices is limited.